Primary emphasis of the investigation will be upon the dynamics of collagen synthesis and degradation in regenerating urodele limbs. Collagen degradation products will be extracted from limbs of various regenerative stages and characterized by gel electrophoresis. Total collagenese activity of limbs will be determined by extracting the enzyme from whole limbs and monitoring release of isotope from C14 collagen. Attempts will also be made to demonstrate cellular sites of collagen synthesis and degradation by using a combination of histochemical and autoradiographic techniques. A secondary goal is the elucidation of nerve-muscle interactions with particular emphasis upon changes in ultra structure of muscle under varying conditions of innervation.